Foldable ladder



United States Patent This invention is a foldable ladder, which comprises a plurality of sections hinged together to fold into '3. stack 1 so as to be readily portable. The several sections are hinged together in endwise relation and are foldable alternately right and left, like an accordion, to form a stack, of a size, for example, that can readily be carried in the baggage compartment of an automobile.

The principal object of the invention is to provide manually operable means for readily locking and securing the ladder in extended, operative position; this locking means comprises a slidable locking bolt adjacent each hinged connection, a series of bolts, such as two, or preferably four, being operable simultaneously to position the bolts across each hinge joint to lock the joint, or to retract the bolts to release the hinged joints. Considering a ladder of two end sections and an intermediate section hinged together endwise, which would require four hinge joints and four locking bolts, a single manually operable handle is operatively connected to all four locking bolts, so that a single manipulation of the handle operates the four bolts to lock the three ladder sections in extended operative position. Latchiug means for securing the operating handle in a position corresponding to the locked and extended position are provided, as a safety measure.

The side rails of the ladder are preferably hollow, channeled or tubular, preferably of light, strong metal, such for example, as aluminum, magnesium or alloys using one or both of these metals.

The locking bolts above referred to are slidable to and from locking position within the hollow side rails of the ladder, and the rods and levers for operating these bolts are housed in the side rails.

Further features of the invention will be described in connection with the accompanying drawings, wherein:

Fig. 1 is a perspective view of the ladder in extended position.

Fig. 2 is an enlarged perspective view of the operating mechanism for two of the locking bolts, in unlocked position.

Fig. 3 is a fragmentary view, showing one of the bolts in locked position.

Fig. 4 is a transverse cross-section on an enlarged scale.

Figs. 5 and 6 are sectional views taken on lines 55 and 6-6 of Fig. 4, respectively.

Fig. 7 is a view showing the ladder in folded position.

Referring now to these drawings, the ladder comprises a number of sections, here five, 1, 2, 3, 4 and 5, hinged together in endwise relation by four hinges 6, 8, 10 and 12, alternately positioned on opposite sides on the side rails 14 and 16 so that the sections are foldable like an accordion alternately right and left to form a stack as in Fig. 7.

The side rails 14 and 16 are hollow, tubular or channeled, thereby providing greater strength and rigidity for a given weight of metal, and also providing space for housing the locking bolts and part of the operating mecha- 2,887,259 Patented May 1 nism for such locking bolts, Solid or tubular rungs .18 are provided as desired. t j 1 Considering an intermediateladder section Figs. 1 and 2, to which is hinged section 1. by hinges 6- and section 3 by hinges 8: slidablymounted in both side rails of section 2 are four locking bolts 20 and 22,,e ach bolt being located adjacent one of the hinges, of anonfiguration as to fit within the side :rail and long enough and strong enough to lock or immobilize the hinge joint when bridged across the joint, as in Fig. 2. Considering the two. bolts 20 and 22ain one side rail,- these bolts are operated simultaneously in. opposite directions-to lockor release the corresponding .hinge, joint. isaccomplished byconnecting rods 20a and 22a,-.eacl1 pivoted to the, respectivebolts at 23 and each pivoted to j a two: armed. lever .24 ineach .side .rail-by a.stirrup 26; and pin 28.

The parts just described for side rail 14 are duplicated in the opposite side rail 16. The two two-armed levers 24 are secured to a transverse operating rod or shaft 30, carried by the side rails and preferably housed in one of the rungs such as 18a, Fig. 4. The operating rod 30 is provided with a handle 32.

When the ladder is unfolded, as in Fig. 1, and the handle 32 is turned clockwise, the four locking bolts are moved in opposite directions to bridge across the respective hinge joints to lock sections 1, 2 and 3 into a rigid unit. Sections 3, 4 and 5 are similarly locked into a rigid unit by a second handle 32a and duplicate locking mechanism. Reverse movement of the handles unlocks all units so that the ladder may be folded into the stack of Fig. 7.

A securing latch or lock is provided as a safety measure, for holding locking bolts in locking position. To this end, the operating rod 30 is provided with a groove or notch 34, adapted to receive a locking pin 36, spring pressed by a spring 38 in a housing 40 secured on the outside of side rail 14. When the handle 32 is in a position in which the locking bolts 20, 22 are in locking position, the locking pin 36 is in groove 34, thereby holding the bolts in locking position. The locking pin 36 is manually retracted to release the handle 32 so that the bolts can be retracted and the ladder folded up.

The top and bottom ends of the ladder are provided as necessary or desirable with caps and footings for keeping dirt and the like out of the channeled, tubular side rails, and for proper positioning of the lower end of the ladder on the ground.

The term tubular for the side rails is intended to cover channeled side rails as well.

While the invention has been described in detail, it should be understood that the invention is not limited to the precise details shown, but may be carried out in other ways.

I claim:

1. A foldable ladder, comprising two ladder sections, each including two parallel side rails, 21 pair of hinges for connecting respective side rails of said two sections, a longitudinally slidable bolt adjacent each hinge connection, being movable in one direction into a side rail of an adjacent section to bridge across and lock said adjacent hinge connection and movable in the other direction to release said hinge connection, a transversely extending rod carried by one pair of side rails and extending substantially at right angles with respect to said side rails, and mounted to rotate on its own longitudinal axis, means operativ'ely connecting said transverse rod to each of said bolts, a manually operated handle for twisting said rod about its longitudinal axis, and means for latching said transversely extending rod when said slidable bolts are in hinge locking position.

2. The combination of claim 1 wherein said transverse 3 operating rod is housed within one of the rungs of the ladder.

3. A foldable ladder, comprising a plurality of sections, including end sections and an intermediate section, hingedtoge'th'er at their respective ends to fold alternately rightsand leftinto a stack, each section having, rungs and t'ubiilarside rails, four bolts longitudinally slidable in thefour' ends of the side rails of said intermediate section, each bolt being movable in one direction into a side rail bfan adjacent section to bridge across and lock an adjacent hinge joint, and movable in the other direction to release said hinge joint, and manual means carried by said intermediate section' for operating said four bolts simultaneously.

4. The combinationof claim 3, further including means for latching said manually'operable means when said bolts are in hinge-locking position.

"SJThe combination of claim 3, said manual means including'an operating rod extending transversely of and carried by the side rails of the intermediate section, and

t A four bolt-operating rods, two in each side rail, operatively connected to said operating rod and to said four bolts, respectively.

6. The combination claimed in claim 5, wherein the connection between said transverse rod and the boltoperating rods comprises two two-armed levers carried by said operating rod and positioned within respective side rails of the intermediate section.

References Cited in the file of this patent UNITED STATES PATENTS 594,303 Ward Nov. 23, 1897 933,816 Bartos et a1 Sept. 14, 1909 1,374,995 Faik Apr. 19, 1921 1,596,282 Lorentzen Aug. 17, 1926 2,183,251 Beggs Dec. 12, 1939 FOREIGN PATENTS Great Britain lanj26 1945 

